Spring框架:spring4.0泛型依赖注入
泛型依赖注入
•Spring 4.x 中可以为子类注入子类对应的泛型类型的成员变量的引用
举个栗子 :
我们新建一个包com.yorkmass.spring.beans.generic.di
在里面新建5个类和一个主类(测试类)如下图:
BaseReposiory类:
package com.yorkmass.spring.beans.generic.di;
public class BaseRepository<T> {
}
BaseService类:
package com.yorkmass.spring.beans.generic.di;
import org.springframework.beans.factory.annotation.Autowired;
public class BaseService<T> {
@Autowired
protected BaseRepository<T> repository;
public void add(){
System.out.println("add...");
System.out.println(repository);
}
}
User类:
package com.yorkmass.spring.beans.generic.di;
public class User {
}
UserRepository类:
package com.yorkmass.spring.beans.generic.di;
import org.springframework.stereotype.Repository;
@Repository
public class UserRepository extends BaseRepository<User> {
}
UserService类
package com.yorkmass.spring.beans.generic.di;
import org.springframework.stereotype.Service;
@Service
public class UserService extends BaseService<User> {
}
新建一个配置文件beans-generic-di.xml
beans-generic-di.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<context:component-scan base-package="com.yorkmass.spring.beans.generic.di"></context:component-scan>
</beans>
Main类:
package com.yorkmass.spring.beans.generic.di;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
ApplicationContext ctx=new ClassPathXmlApplicationContext("beans-generic-di.xml");
UserService userService=(UserService)ctx.getBean("userService");
userService.add();
//UserService继承BaseService
//UserRepository继承BaseRepository
//UserService、UserRepository都被注解
//BaseService被@Autowire自动装配,注入BaseRepository<User>子类对象UserRepository
}
}
运行结果:
一月 18, 2019 12:23:49 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1405ef7: startup date [Fri Jan 18 12:23:49 CST 2019]; root of context hierarchy
一月 18, 2019 12:23:49 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [beans-generic-di.xml]
add...
com.yorkmass.spring.beans.generic.di.UserRepository@1921e20
整合多个配置文件
•Spring 允许通过 <import> 将多个配置文件引入到一个文件中,进行配置文件的集成。这样在启动 Spring 容器时,仅需要指定这个合并好的配置文件就可以。
•import 元素的 resource 属性支持 Spring 的标准的路径资源
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